Vane-type rotary machines are known and consist of a rotary body, arranged eccentrically in a stationary housing. Vanes are radially slidable in slots provided in the body and counterweights are used to act on the vanes to reduce the centrifugal forces arising when the rotary body is in operation. The vanes must always remain in contact with the interior profile of the housing in order to prevent any fluid circulation or heavy leakage between moving chambers defined by the vanes, the inner profile of the housing and the outer profile of the rotary body. To meet this objective, it is essential that vane pressure be always positive by a non-negligible amount in order to prevent any lifting of the vanes from the housing, which lifting may be either produced by external causes or by the reversal of centrifugal positive force produced by the acceleration induced by the radial displacement of the system vane-counterweights.
One way to insure that there will be no lifting of the vanes from the inner profile of the housing and no significant leakage between the chambers and that the vane pressure on the housing will remain fairly small is by the adoption of:
(a) a double vane system; PA1 (b) a housing configuration of an odd order with constant diametrical chord; and PA1 (c) a symmetrical system of counterweights that will take into account, not only the centrifugal action of the double mass system, but also the very important acceleration produced by the movement of the vane system in a non-circular housing. PA1 (a) a stationary housing having an interior profile defining a monolobic configuration; PA1 (b) a rotary cylindrical body having an axis of rotation arranged eccentrically in this housing, the body including a series of arc-shaped segments mounted in circular alignment in the housing and being equally spaced from one another to define therebetween a series of diametrically opposite slots; PA1 (c) interfitted double vanes slidably received in the slots, each double vane being longer than the diameter of the body and including diametrically opposite blade portions, these double vanes being diametrically shiftable in the slots during rotation of the body; and PA1 (d) counterweight means mounted in the body and disposed adjacent each blade portion;
With respect to housing configuration, it is considered, however, that a third, or higher, order configuration will not provide satisfactory results due to the very high component of the acceleration produced by the radial displacement of the vanes.
Some systems are known which rely on the centrifugal action of simple vanes. However, it is known that such known constructions do not take into account the acceleration produced by the radial displacement of the vane-counterweight system. It is to be remembered that, contrary to the centrifugal acceleration, the radial acceleration produced by the radial displacement acts on the total mass of the system and not only on the mass of the blade or of the counterweights. Furthermore, these known constructions do not take into account the lifting of the vane in a certain portion of its cyclic movement thereby resulting in corresponding circulation or heavy leakage between chambers. Furthermore, these systems do not take into account the vibratory motion produced by the vane lifting followed by the subsequent knocking of the same vane on the housing in another portion of the cycle.
In fact, instead of reducing vane pressure on the housing, some of the known systems, which are based only on balancing the centrifugal action, actually increase the vane-system pressure in a decreasing radius section of the housing where a corresponding negative value of the radial displacement is achieved.